Urgency and frequency are common lower urinary tract symptoms (LUTS) in women and are accompanied by substantial activity and participation restrictions. Medical management begins with ruling out organ pathologies, typically followed by fluid intake and timed voiding often combined with pharmacologic management, and may progress to nerve stimulation, botulinum injections, or surgery where indicated. Despite abundant management options for urgency and frequency predominant LUTS (UF-LUTS) and high financial burden, patients often experience only partial relief from medical treatments for LUTS. While a great deal of literature exists to inform pharmacologic and surgical care of patients with UF-LUTS, less is known about the movement system and its relevance to UF-LUTS. This project sought to inform our understanding of movement system components that may influence either the individual’s experience of the symptoms or associated activity and participation restrictions with the hope that our work may eventually inform nonpharmacologic or nonsurgical treatment. Pelvic floor muscle (PFM) strength and endurance are typical body function intervention targets in patients with UF-LUTS as they may be necessary to engage the voluntary urinary inhibition reflex. But PFM strength and endurance have not been studied in participants with and without UF-LUTS. Alternatively, some have theorized that PFM strength and endurance may not be the most important targets in patients with UF-LUTS, and suggested that instead, PFM overactivity or impaired mobility may be more important to assess and treat. Clinical observations suggest PFM mobility is impaired in patients with UF-LUTS and this has been theorized to contribute to impaired pelvic circulation and/or reduced degrees of freedom for of neural structures innervating the urinary system and related musculoskeletal structures.

Overall, the focus of this project was to understand how body functions of PFM strength, PFM mobility and hip muscle strength differ between women with UF-LUTS and control participants without UF-LUTS, and if these factors are associated with symptoms and the impact of those symptoms on activity and participation. In Chapter 2, we compared hip and PFM strength in women with and without UF-LUTS. We hypothesized that cases with UF-LUTS would have weaker hip external rotator and abductor muscles, similar PFM strength, and poorer PFM endurance than controls without UF-LUTS. Our first hypothesis was supported:​ our results showed that women with UF-LUTS had weaker hip external rotator and abductor muscles. We did not find differences in PFM strength or endurance between women with and without UFLUTS. Our study was underpowered to detect case-control differences in PFM strength and endurance, so we cannot say with certainty that no differences exist.

In Chapter 3, we used dynamic transperineal ultrasound imaging to compare PFM position and mobility in women with and without UF-LUTS. We hypothesized that women with UF-LUTS would demonstrate elevated resting position of the PFMs and decreased pelvic landmark excursion in relation to pelvic landmarks during contraction and during bearing down as compared to women without UF-LUTS. Our hypothesis was partially supported. Compared to those without UF-LUTS, women with UF-LUTS demonstrated a significantly greater levator plate angle at rest (more cranial and anterior PFM position) and less pelvic landmark excursion (puborectalis muscle lengthening) from rest to bearing down.

This project highlights hip muscle strength and pelvic floor position/mobility as body functions of likely importance in women with UF-LUTS. We discovered that women with UF-LUTS have weaker hip external rotator and abductor muscles, more elevated resting position of the PFMs, and poorer pelvic landmark excursion (PFM lengthening) when cued to bear down than women without UF-LUTS. Clinical assessment of hip muscle strength and PFM position and mobility may better inform nonpharmacological treatment of patients with UF-LUTS. Further work is needed to better understand the mechanisms underlying these relationships and the efficacy of addressing these impairments through intervention.